Javascript MCQ

JavaScript MCQs

   

MCQ 1

Question: Which JavaScript method can be used to convert a string into an array of characters?

   A. split()

   B. join()

   C. charAt()

   D. substr()

Answer: A. split()

MCQ 2

Question: What is the output of the following code snippet?

let x = 5;

let y = 10;

let z = x++ + y--;

console.log(z);

    A. 14

    B. 15

    C. 16

    D. 17

Answer: B. 15

Explanation:

  x++ increments x after the expression is evaluated, so it becomes 6.

  

y-- decrements y after the expression is evaluated, so it becomes 9. Therefore, 

  z = 6 + 9 = 15.

Hence , the output is 15.

JavaScript MCQs with getElementById

MCQ 1:

Question: What is the correct way to get an element with the ID "myDiv" using the getElementById() method?

    A. document.getElementById("myDiv")

    B. getElementById("myDiv")

    C. document.get("myDiv")

    D. document.find("myDiv")

Answer:  A. document.getElementById("myDiv")

MCQ 2 :

Question: How can you change the inner HTML of an element with the ID "myParagraph" to "Hello, world!" using the getElementById() method?

 A. document.getElementById("myParagraph").innerHTML = "Hello, world!";

 B. document.innerHTML("myParagraph", "Hello, world!");

  C. myParagraph.innerHTML = "Hello, world!";

  D. document.write("Hello, world!");

Answer:

 A. document.getElementById("myParagraph").innerHML = "Hello, world!";

MCQ 3 :

Given an array fruits = ["apple", "banana", "orange"], how can you create a new array containing only the fruits that start with the letter "a"?

  A. fruits.filter(fruit => fruit.startsWith("a"))

  B. fruits.map(fruit => fruit.startsWith("a"))

  C. fruits.reduce((acc, fruit) => fruit.startsWith("a") ? [...acc, fruit] : acc, [])

  D. fruits.forEach(fruit => fruit.startsWith("a") ? console.log(fruit) : null)

Answer: A. fruits.filter(fruit => fruit.startsWith("a"))

The filter() method is used to create a new array containing only the elements that pass a test (in this case, starting with the letter "a").

MCQ 4 :

What is the output of the following code?

const numbers = [1, 2, 3, 4, 5];

const squaredNumbers = numbers.map(num => num * num);

console.log(squaredNumbers);

  A. [1, 4, 9, 16, 25]

  B. [2, 4, 6, 8, 10]

  C. [1, 2, 3, 4, 5]

  D. An error will be thrown.

Answer: A. [1, 4, 9, 16, 25]

The map() method creates a new array by applying a function to each element of the original array. In this case, the function squares each number.